#include <bits/stdc++.h> using namespace std;

double sq(double x) { return x * x; }

double dist(double x1 , double y1 , double x2 , double y2 ) { return sqrt(sq(x2-x1)+ sq(y2-y1)); }

int main() { double x1 , x2 , x3 , y1 , y2 , y3 , sum = 0; cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3; sum = dist(x1 , y1 , x2 , y2)+dist(x1 , y1 , x3 , y3)+dist(x2 , y2 , x3 , y3); cout << fixed << setprecision (2) << sum; return 0; }